Improvement in rotary engines



W. M. STEVENSON.

Rotary-Engidef W Q w@ .I RN. m

UNITED STATES PATENT QEEroE.

WILLIAM VM. STEVENSON, OF SHARON, PENNSYLVANIA, ASSIGNOR OF ONE-HALF HISRIGHT TOWILLIAM MCGILVRAY, OF SAME PLAGE.

IMPROVEMENT IN` ROTARY ENGINES.

Specification forming part of Letters Patent No. 167,134, dated August24, 1875; application filed April 20, 1875.

To all whom it may concern:

Be .it known that I', WLLLIAM M. STEVEN- SON, of Sharon, in the countyof Mercer and State of Pennsylvania, have invented certain new anduseful Improvements in Rotary Engines; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, which willenable others skilled in the art to which it pertains to make and usethe same, reference being had to the accompanying drawing, and to theletters of reference marked thereon, which form a part of thisspecification.

My invention relates to rotary engines and the invention consists incertain improvements in the construction and arrangement of the parts,whereby the operation of such engines is rendered more perfect, and theobjections heretofore existing' to their use obviated.

My engine is so constructed that it may be reversed at any point of arevolution, and will work with like facility in either direction. It isof comparatively simple construction, easily operated, and occupies buta small space as compared with otherdescriptions of engines. y

In the accompanying drawings, Figure l is a sectionalview, showing theconstruction of the revolving drum, pistons, valves, 85o. Fig. 2 is aview of the inner side of one of the covers, showing the cam-plate orpiston-carrier attached thereto. Fig. 3 is a sectional view, showing thebearings and device for adjusting the same. Fig. 4 is a view showing aportion of the upper cylinder and the form of the zigzag ports. Fig. 5is an enlarged View of a portion of one of the pistons, showing itsconstruction.

Referring to the parts by letters, A represents the under half of thecylinder, the inner periphery of which is a true arc ofa circle. A isthe upper half or portion ofthe cylinder containing the steam andexhaust ports. It

is of the same diameter as the lower portion A at the point of contactwith the latter; but,

instead of its inner periphery being the truearc of a circle, like thelower portion, it is parabolical, or two arcs from different centersunited by a plane, as clearly shown in Fig. l ofthe drawings. The twovhalves of the cylinder are provided with projectingl anges a `volvetogether.

lever being pivoted to an arm, d, the inner end of which is pivotedbetween the projecting ears of a plate, E, which is secured to theportion A of the cylinder. F F are the steam-ports leading from thesteam-chest to the interior of the cylinder. They are formed taperingand of a peculiar zigzag form, and with double channels converging atthe ends, as clearly shown by Fig'. et of the drawings. Gr isthe'eXhaust-cavity formed on the under side of thevalve C, andcommunicating with` one or other of the ports F, and with the eductionor exhaust port H. I is the induction-port, leading into thesteam-chest. K is the drum, madeoylindricalin form, and keyed to thecentral shaft J, so that they both re- The drum K is made hollow or witha cavity, L, which communicates with the steam-space within the cylinderby means of check-valves, which may be provided with diaphragms Z l, fora purpose hereinafter described.

m m are two radial grooves, formed in the drum K for the reception ofthe pistons, and in which the pistons are made to slide back and forth,or reciprocate, as hereinafter set forth. M represents one form of thepiston. It is made hollow by core or otherwise, and the inner end isprovided with a shoe, n, of brass or other suitable material, which isset into a groove formed in the under side of the piston. The other endis provided with a liXed shoe, N, of brass or other' suitable mate.-rial, and the sides are provided with packing a', which is held againstthe sides of the grooves m by means of the force oi steam, which findsits way from the hollow piston through a lateral channel, o, to the rearside of the packing, as shown by. dotted lines, Fig.

`5. M represents a piston, constructed the same as the piston M, exceptthat, instead of the fixed shoe N, it is provided with an oscil latingshoe, N', which rocks or oscillates upon a circular head on the end ofthe piston, so as to conform and fit close to the cylinder as the drumrevolves. Two or more coiled springs, p. are placed in the pistonsbetween the shoes N n or N fn', which hold them in place, yet permit theinner shoes to yield or vibrate within the grooves in the inner end ofthe piston. P represents the piston carriers, cam shaped disks or ringsof metal attached to the inner side of the cylinder-heads, and fittingwithin the sides of the cylinder-drum, in contact with the inner pistonshoes n. Q represents the inner face of one of the cylinder-heads,having an annular groove, q, formed therein for the reception of theannular projecting edge or faceof the drum K, metallic or other suitablepacking R being inserted in the groove, and held against the edge of thedrum by a wire spring, r, or other suitable means. T represents one ofthe bearing boxes for the shaft, having an inner hub, which passesthrough the cylinder-cover, suitable packing heilig provided betweenthem. The outer ends of the bearings are provided with screw-caps U, tokeep out the dust and other extraneous matter. V represents a device foradjusting and sustaining the bearingboxes in proper position. Itconsists of a lever,v, pivoted between the uprights or standards w of aplate, W, which is secured to the cylinder-cover or frame ofthe machine.The upper end of the lever c is turned inwardly, and fits a grooveformed in the periphery of the bearing-box for its reception. rI lhelower end of the lever is cut with an elongated slot, fu', through-whichand into the plate lW a thumb-screw or bolt, fw', is passed. Anadjusting and sustaining device of this description may be provided forboth bearing-boxes.

The operation of my invention is as follows: When it is desired to startthe engine, the throttle valve is opened, and steam is admit ted throughthe port I to the steam chest. The valve is then moved by the handle D,so as to open one or other of the steam ports F F', according to thedirection in which the shaft is desired to be revolved. If tothe left,the valve will be pushed in, as shown in Fig.

` l, thereby admitting steam through the port F in the direction shownby the arrows, and, pressing against the piston M, will cause the drum Kand shaft J to revolve. The end of the piston is kept in positionagainst the interior periphery of the cylinder by means of the cam-plateor piston-carrier P, the periphery of which corresponds in form with theinterior of the cylinder, and as thev drum revolves the piston M passesthe steam-port, and receives the full force of the steam when the pistonM passes the exhaust-point, which begins at the junction of the upperand lower portions ofthe cylinder.

The exhaust steam passes through the port F to the exhaust-cavity G, andfrom thence through the eduction-port H. The flat top or plane portionofthe upper half-cylinder forms the steam abutment between the ports,and this portion of the cylinder bein'g always in contact with the drumor'shoes of the pistons, no steam can pass this point. The shoes arealways kept in contact with the inner periphery of the cylinder by meansof the cams or carriers P, which causes them to reciprocate back andforth in the grooves m, so that no steam can pass the pistons. It willbe seen, therefore, that as long as the port F is open for the admissionof steam, the drum and shaft will continue to revolve to the left, thesteam exhausting through the port F. When it is desired to reverse theengine, the lever I) is moved outwardly, so as to slide the valve acrossthe steam-chest, thereby opening communication between the steam-chestand the port F, establishing communication between the port-F and theexhaust G, when the drum and shaft will revolve to the right.

It will be obvious to those skilled in the art that by this arrangementof the ports, the pistons, and the revolving drum, the force of thesteam is applied in the lower or working half ofthe cylinder, and thatby exhausting at the junction of the lower and upper halves there islittle or no resistance to the revolution of the drum and shaft by backpressure, and that the engine may be reversed at any point of arevolution. By moving the valve to the center of the steam chest boththe ports are closed and the engine stopped. It will also be seen thatsteam is admitted to the interior of the piston-drum b v means of thecheck-valves l Z, thereby serving the double purpose of balancing thepressure on the pistons, and, through the pistons being made hollow andcommunicating with the steamspace in the hollow drum, aiding in keepingthe shoes against the periphery of the cylinder and the packing n in theproper position.

The peculiar tapering and branched form of the zigzag portsgF F servesto diffuse the steam and prevent it from acting injuriously against anyone portion of the surface of the druman ei'ect it would have ifinjected through a straight port, so as to continually act with itsfullest force against one particular portion of the drum surface. Thispeculiar form of the ports also enables the.steam to exhaust morerapidly, thereby offerin g less resistance to the revolution of thedrum. The drum and shaft are journaled centrally with the lower halfA ofthe cylinder by the adjustable-bearing-boxes T; and should the drumbecome worn through friction, or otherwise drop, so as not to form aclose connection or fit with the steam-abutment or plane part of theupper pai-tion of the cylinder, it can be raised by means of theadjusting devices V, a turn or two upon the screws w accomplishing thedesired result.

Having thus described my invention, what i l i l l l l l l I claim asnew, and desire to secure by Letters Patent, is-

1. The graduated and zigzag ports F F', constructed substantially as andfor the purpose specied.

2. The combination of the zigzag ports F F', valve G, exhaust G E, andsteam-chest B with the oylinderA A and piston-drum K, all operatingsubstantially as and for the purpose specified.

3. The pistons M, having shoes N n, springs p, and packing n', andarranged to reciprocate within the grooves m of the drum K, in themanner substantially as and for the purpose set forth.

4. The combination of the cylinder-covers Q, drum K, and cylinder A A'with the adjustable bearing-boxes T, substantially as and for thepurpose specified.

5. The combination of the cylinder-covers Q with the adjustablebearing-boxes 'I and the adjusting device V, substantially as and forthe purpose specified.

In testimony that I claim the foregoing as my own I aHX my signature inpresence of two witnesses.

WM, M. STEVENSON. Witnesses:

ABNER APPLEGATE, JOSEPH J. RIG'BY.

